12 D. B. CASTEEL 



ing the results of tests for Pattern and for Line Discrimination, 

 form the major portion of the work. 



BLACK AND WHITE DISCRIMINATION 



In these tests the boxes used were painted black and white 

 respectively. Tests with turtles Nos. i and 2 were conducted 

 without the use of the electric shock for punishment, food being 

 the only incentive to success and forcible return to the entrance 

 room without reward the only punishment. The apparatus 

 used with these turtles was somewhat different from that already 

 described, being less elaborate and, of course, lacking all elec- 

 trical connections. 



Turtle No. i was given, as a rule, ten trials in succession 

 every other day. On several days the turtle was sluggish and a 

 fewer number of trials necessary. In a few instances more 

 than one day intervened, necessitated by the animal's lack of 

 eagerness and activity. It was fed in the white box only. In 

 this experiment no preference tests were taken. The results, 

 given in table i, show that an association between the white 

 box and food was clearly established. The result of the tests 

 for memorv is also to be noted. 



ml 



Turtle No. 11 was fed in the black box. It was induced to 

 enter this box twelve times before the actual tests were begun. 

 In all other respects it was treated in a manner similar to No. i. 

 Its record, given in table 2, shows but two perfect tests although 

 the general average of successful trials is good. The two memory 

 tests, taken twelve and twenty-one weeks after the last test 

 of the series, are not perfect though as good as that test. 



Turtles Nos. 8, 9, and 13 were tested with black and white 

 boxes during the latter course of the work for the sake of obtain- 

 ing additional evidence for or against this type of discrimination. 

 Preference tests were made in all cases and the electric shock 

 was used as punishment. Both No. 8 and No. 9 had, in a pre- 

 vious experiment for pattern discrimination, been accustomed 

 to entering black boxes on which white patterns were displayed. 

 Their decided preference for black may thus be explained. In 

 both cases the food box w^as white so that the former preference 

 had to be overcome. No memory tests were taken. The records 

 of these turtles for black and white are found in tables 3 and 4. 



Turtle No. 13 was decidedly the most unsatisfactory animal 



